1. Field
The present application relates to an image processing apparatus and an image processing method.
2. Description of the Related Art
Conventionally, as a method of obtaining an image with good contrast, there has been formed a synthetic image whose dynamic range is extended by synthesizing a plurality of pieces of input images obtained by shooting a same scene and having different exposure amounts. Further, there has been proposed a method of performing tone conversion based on the synthetic image with wide tonal range (high-contrast image), and generating an output image as a final result having a narrower tonal range than the synthetic image (Japanese Patent No. 3956311, for example).
With the use of this method, there is generated the output image in which information (particularly, tone information) of the high-contrast image with wide tonal range is held, which enables to obtain an image with good contrast.
In the above-described conventional method, it is designed to perform the tone conversion for generating the output image as a final result, in accordance with a conversion characteristic calculated based on features, concretely, three feature points of a minimum brightness value, an intermediate brightness value and a maximum brightness value of a brightness distribution of the high-contrast image (synthetic image). However, in the tone conversion, there still have been problems such that a tone jump occurs, and particularly, a tone expression in a low brightness part and a high brightness part of the image becomes unnatural. For this reason, it was not possible to obtain an image with good contrast as an output image being a final result.